L1 Lumamax head on an E1e body, is this a safe setup?

I know the L1's head will fit on an E1e body, and i'm aware that the L1 head is a "dumb" head, no regulation electronics, the LED would be running purely in direct-drive mode, according to my cheapo Radio Shack DMM, the L1 puts out around 6.2V to the head on high (must be a boost circuit in the head)

the L1 puts out around 3V or so, depending on battery capacity, it's essentially a simple open circuit

on paper, it looks like the L1's head could handle 3V direct drive, unless the regulation electronics in the L1's head do something else i'm not aware of, all i'm wondering is if it's safe to use the L1 head on the E1e, i don't want to end up damaging the LED or burning it out or otherwise shortening it's lifespan, and yes i understand the head will be in direct drive mode, gradually dimming as the battery drains

is it safe to run an L1 head on an E1e using primary cells only?

The L1 head with a white LED will work on a E1e with a primary cell, but it will be dimmer than normal. It will not harm the luxeon to be underdriven.

I think a L1 head on a E1e body with one primary cell with a green or blue Luxeon would be the the same as white.

A L1 head with a red LED on a E1e with one primary cell appears to be about the same brightness as a KL1 with a red Luxeon or a L1 with a red Luxeon.

The white, (& I think the green & blue) are underdriven while it appears the red is driven close to specks.

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Just in case anybody is wondering, the L2 head works just fine on 2x123 primary cells, but it is underdriven.